The invention relates to a device for locking a swiveling actuating lever of a shifting device of a gear-change mechanism of a motor vehicle in a lever position associated with a particular shift state as a function of the position of a brake pedal. The swivellably mounted actuating lever is in operative connection with a counter-blocking locking element moved by brake pedal via a mechanical adjusting linkage. The actuating lever is provided with a blocking member that cooperates with the counter-blocking locking element. The locking element can be moved by a restoring spring, holding the brake pedal in an unactuated rest position, into a locking position holding the blocking and counter-blocking members in engagement. When the brake pedal is depressed, the spring force of the restoring spring is overcome and the linkage is moved into a floating position bringing the blocking and counter-blocking members out of engagement. The adjusting linkage contains a resiliently-acting intermediate member for changing the effective linkage length and the intermediate member is designed with lower spring forces than the restoring spring. The actuating lever has at least one nonlockable lever position associated with a particular shift state(s) where the blocking and counter-blocking members are disengaged. In the unactuated rest position of the brake pedal, the locking element is held in its floating position by actuation of the actuating lever between nonlockable lever positions and the spring force of the intermediate member is overcome to change the linkage length of the adjustable linkage. Thus the pedal can remain in its rest position.
In a known device of this general kind (U.S. Pat. No. 4,096,930), a manual selector of an automatic gear-change mechanism is mounted as a steering column shift on a vehicle steering column. The arrangment is such that the brake pedal is articulatedly connected to a connecting rod which leads to the manual selector lever and is connected by a resiliently-acting intermediate member (in the form of a prestresses compression spring) to a locking pin which can move into two receiving holes of a locking disk firmly connected to the manual selector lever. One of the receiving holes is aligned with the locking pin in the park position and the other in the neutral position of the manual selector lever. Unlocking of the manual selector lever is accomplished by depressing the brake pedal, which, due to its articulated connection to the connecting rod, provides a positive coupling with the locking pin.
Due to the use of a rigid connecting rod, this construction is not readily suitable for the locking of a manual selector lever arranged in the manner of a floor shift on the transmission tunnel because, by its very nature, a simple connecting rod cannot be accommodated between the brake pedal and such a manual selector lever. Also if, as a consequence of an accident or the like, the connecting rod is damaged, there is the risk that the manual selector lever will be impossible to unlock and/or the brake pedal will be impossible to actuate.
The object on which the invention is based consists essentially in creating a device for locking the actuating lever of a shifting device of a gear-change mechanism, arranged as a floor shift next to the driver's seat as a function of the position of the brake pedal, wherein the actuating lever can also assume nonlockable lever positions and wherein hydraulic means are not used (for safety reasons) and a breakage of mechanical linkage elements cannot lead to an impairment of the shifting device.
The object of the invention is achieved in an advantageous manner by having an adjusting linkage of flexible design and the locking element be swivellably mounted and actuable by a resilient means into a floating position. The spring forces of the resilient means are less than the spring forces of a resilient intermediate member connecting the brake pedal to the locking element. The resiliently-acting intermediate member has two levers which are mounted about a common swivelling axis and are relatedly held to one another by the spring forces and by a stop and counter-stop means. One of the levers can be brought into engagement with the brake pedal and the linkage end of the adjusting linkage which is associated with the brake pedal cooperates with the other lever.
The locking mechanism is located at the actuating lever and consists of a cam disk part which is arranged concentrically to the swivelling axis of the lever to be moveable therewith. The disk has blocking and control cams which cooperate with the locking element connected to the brake pedal. For installment adjusting purposes the one lever of the intermediate member (associated with the brake pedal) is connected both by a releasable frictional connection and by an adjusting spring to a cam lever mounted so as to be swivellable about the common swivelling axis of the intermediate lever. With the frictional connection released, a lever moment which brings the cam lever up against the brake pedal, is obtained by fixing the one lever of the intermediate member relative to a part fixed to the vehicle.
As an extra desirable feature the locking element can be actuated into its floating position, irrespective of the position of the brake pedal. Here an electromagnet operates as a function of the driving speed to provide the additional control. The electromagnet, is arranged in proximity to the brake pedal and acts on a linkage part connecting the resiliently-acting intermediate member to the locking element.
A still further extra feature is to have the actuating lever lockable in park position as a function of the position of an ignition lock. The ignition lock is provided with a single fixed angular key withdrawal position. A camshaft part is actuable by turning of the ignition key and has a blocking cam that cooperates with a locking slide displaceable perpendicularly to the axis of rotation of the camshaft part. The slide has a corresponding counter-blocking cam. The camshaft part also has control cam surfaces and the locking side a corresponding counter-control cam surface. When the ignition lock is actuated by a key in the direction of a driving position, the locking slide moves into a locking position in which the counter-blocking cam lies in the path of motion of the blocking cam and thereby blocks the key from returning to its withdrawal position unless the actuating lever is in the park position. The control between the ignition lock and the actuating lever includes a flexible mechanical adjusting linkage cooperating with the locking slide through a resilient means which can move the locking slide into a floating position in which its counter-blocking cam lies outside the path of motion of the blocking cam. Here the lock cylinder core is thus free to reach the key withdrawal position. The resilient means for the floating position of the locking slide is designed with higher spring forces than the resilient means for the adjustable linkage connection to the locking element. The adjusting linkage of the locking slide is connected to the intermediate lever through a lost motion connection that allows the intermediate lever to be positioned differentially with respect to the locking slide. The swivellable locking element can be actuated into its locking position by the resilient means of the locking slide.
The lost motion idle path of the linkage connection is operative when the brake pedal is in its rest position and, simultaneously, both the swivellable locking element and the locking slide are each in their respective locking positions.
When the swivellable locking element is actuated into its floating position by the actuating lever moving out of park, the locking slide prevents key withdrawal. It is possible to actuate the lock into its key withdrawal position, irrespective of the position of the brake pedal, only when the actuating lever is in park position. Also and irrespective of the position of the brake pedal, the actuating lever is locked in its park position when the lock is in its key withdrawal position.
Alternatively, the actuating linkage for the locking mechanism can operate on the locking member of the actuating lever directly rather than going through the intermediate lever. Here also a lost motion connection is utilized. A second bias spring can be provided at the end of the linkage adjacent the locking mechanism to allow for key locking control in other than a parking position. To that end a control cam on the locking means is provided between two blocking cams associated with the actuating lever to provide for a nonlockable lever position lying between two lockable lever positions.
While the embodiments are chiefly directed at the use of the invention for a practical installation of components in proximity to the brake pedal, functional advantages are also achieved by some of the further developments, such as: an additional ignition lock-dependent locking of the park position; an additional brake-pedal-dependent locking at a neutral position; and a driving-speed-dependent prevention of the locking at the neutral position.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.